Convoy OB 318 and the capture of U-110

7–10 May 1941, North Atlantic, south of Iceland and east of Cape Farewell

British success; U-110 captured with her Enigma machine and code books

U-boats found outbound convoy OB 318 south of Iceland on 7 May 1941 and sank seven ships in four days. On 9 May Fritz-Julius Lemp in U-110 torpedoed two ships, but the corvette Aubrietia picked up his periscope on her ASDIC, and her depth charges, with the destroyers Broadway and Bulldog, forced U-110 to the surface. Bulldog turned to ram, and Lemp's crew abandoned ship, thinking she would sink. Commander Joe Baker-Cresswell turned away instead and sent a boarding party under Sub-Lieutenant David Balme, which brought out her Enigma machine, its settings and her code books. Lemp, swimming back to destroy them, was never seen again. U-110 sank under tow two days later, which helped keep the capture secret: her crew were kept apart from other prisoners and never knew. The papers helped Bletchley Park read the U-boat cipher for months afterwards.